As known in the prior art, metal hydrides are particularly useful for the generation of hydrogen gas whenever the use of compressed gas is inconvenient or infeasible due to storage considerations. The metal hydrides lead in hydrogen-generating capacity per unit weight. Sodium borohydride, for example, can react slowly with water, but more quickly in the presence of a transition metal catalyst, to liberate four moles of hydrogen gas per mole of the compound, or 2.4 liters H2 gas per grams of compound (L/g) at room temperature, as shown in Equation (1):                Transition Metal Acc.NaBH4+2H2O(l)→NaBO2+4H2(g); ΔH=−72.5 kcal/mole  Eq. (1)As can be seen from the above, transition metals can be used as accelerators for generation of hydrogen in many applications, and particularly in conjunction with sodium borohydride. In addition to its large hydrogen generating capability, sodium borohydride can have a number of advantages over the metals and other metal hydrides, in that it is readily available in granular form at a moderate price, it is stable for months in alkaline solution, its solubility in water is high, and it is relatively safe to handle, especially when it can be transported and stored in dry form. But for other applications, in particular those that envision that use of seawater for interacting with metal hydrides to generate hydrogen, transition metals can be ineffective as accelerators for reactions that involve sodium borohydride.        
One possible solution could be to use acid accelerators, vice transition metal catalysts, when generating hydrogen from metal hydrides and water. Prior studies are known in the art for describing the effect of acid accelerators and catalytic accelerators on the evolution of hydrogen gas from sodium borohydride, but in pure (DI) water. Other studies in the prior art can describe the evolution of hydrogen gas from lithium borohydride using steam as an accelerator. There is also prior art that can describe the generation of hydrogen gas from metal hydrides and seawater, as opposed to pure water, using acid accelerator NaHSO4. But in the prior art, the disclosed methodology refers to an open system and can be only thirty to fifty percent efficient. This can be an ineffective efficiency level for many applications, especially for applications which are space or weight-limited, and would require that the amount of acid accelerator used be kept to a minimum.
In view of the above, it can be an object of the present invention to provide methods and apparatus for generating hydrogen that use acid accelerators, instead of transition metal accelerators. Another object of the present invention can be to provide methods and apparatus for generating hydrogen that use seawater as a reactant in hydrogen generation, which can allow for subsea hydrogen generation without having to transport DI water reactant to the reaction site. Another object of the present invention can be to provide methods and apparatus for generating hydrogen with starting materials that are stable for long periods of time, for ease of storage. Still another object of the present invention can be to provide methods and apparatus for generating hydrogen that are sufficiently efficient for undersea naval applications. Yet another object of the present invention can be to provide methods and apparatus for generating hydrogen that can generate sufficient hydrogen yield to function as part of a hydrogen source for an underwater fuel cell. Yet another object of the present invention can be to provide methods and apparatus for generating hydrogen using seawater that can be easy to implement in a cost-effective manner.